1. Field of the Invention
The present invention relates to a control system that carries out traction control of a vehicle and a vehicle including the same.
2. Description of the Related Art
As systems for preventing four-wheel motor vehicles from slipping, traction control systems (see, for example, JP 2000-344083 A and JP9-249050 A) have been conventionally developed.
In a traction control apparatus for a vehicle disclosed in JP 2000-344083 A, for example, when the amount of idling of a drive wheel exceeds an allowable slip amount, a braking force is applied to the drive wheel. Thus, the idling of the drive wheel is suppressed within the allowable slip amount.
Furthermore, in a vehicle driving force controller disclosed in JP 9-249050 A, for example, when excessive slip of a drive wheel is detected, a driving force of the vehicle is reduced such that the slip ratio of the drive wheel converges on a target slip ratio.
It is preferable that driving forces (traction) of drive wheels of vehicles are controlled depending on traveling states of the vehicles. Therefore, in JP 2000-344083 A, described above, when a sub transmission is in a low-speed state, the allowable slip amount is set to a low value. Further, in JP 9-249050 A, described above, when the shift position of an automatic transmission is forcibly changed to the second position, the target slip ratio is reduced. That is, in JP 2000-344083 A and JP 9-249050 A, traction control of the drive wheel is carried out depending on the state of the transmission.
In JP 2000-344083 A and JP 9-249050 A, however, the traction control of the drive wheel is carried out on the basis of the state of the transmission. Therefore, traction control suitable for a vehicle speed cannot, in some cases, be carried out.